The use of proteases of the subtilisin type is preferred for washing and cleaning agents. The proteases used in the washing or cleaning agents known from the prior art either originally originate from microorganisms, for instance of the genera Bacillus, Streptomyces, Humicola, or Pseudomonas, and/or are produced by suitable microorganisms using per se known biotechnological methods, for instance by transgenic expression hosts from the genera Bacillus or by filamentous fungi.
Further enzymes, in particular amylases, are increasingly present in particular in modern liquid washing agents. An amylase is an enzyme which catalyzes the hydrolysis of glycosidic bonds, in particular in polysaccharides such as starch. Among amylases, α-amylases, which hydrolyze the α(1-4)-glycosidic bonds in amylose are often used in washing and cleaning agents. Within the EC classification of enzymes, the numerical classification system for enzymes, α-amylases have the EC number (“Enzyme Commission number”) 3.2.1.1 and consequently belong to the third of the six main classes of enzymes, the hydrolases (EC 3.-.-.-), then to the glycosylases (EC 3.2.-.-) and in turn to the glycosidases (EC 3.2.1.-), i.e. enzymes which hydrolyze O- and/or S-glycosyl compounds. Starch breakdown by α-amylases gives rise to dextrins and, from the latter, maltose, glucose and branched oligosaccharides. Amylases consequently in particular act against starch-containing residues on laundry and catalyze the hydrolysis thereof.
International patent applications WO95/23221 and WO92/21760 disclose variants of the alkaline protease from Bacillus lentus DSM 5483 which are suitable for use in washing or cleaning agents, as well as washing and cleaning agents containing such proteases. International patent application WO2011/032988 furthermore discloses washing and cleaning agents which likewise contain variants of the alkaline protease from Bacillus lentus DSM 5483. The protease variants disclosed in said documents may be modified, in addition to further positions, in positions 3, 4, 99 and 199 in the numbering system for the alkaline protease from Bacillus lentus DSM 5483 and for example have amino acids 3T, 4I, 99D, 99E or 199I in the stated positions. It is furthermore disclosed that the washing agents may contain further enzymes, also including an amylase. The washing agents may be solid or liquid. Said document does not, however, directly and unambiguously disclose a liquid washing agent which contains an amylase in combination with a protease which has combinations of these modifications as are described hereinafter.
A disadvantage of prior art protease- and amylase-containing liquid washing and cleaning agents is that they have inadequate storage stability and they accordingly lose a considerable degree of enzymatic, in particular amylolytic and/or proteolytic, activity after only a short time. The presence of protease frequently leads to the loss of amylolytic activity, since the protease inactivates the amylase. The washing or cleaning agent then no longer exhibits optimum cleaning performance.
It is an object of the present invention to overcome the stated disadvantage and to provide protease- and amylase-containing liquid washing or cleaning agents which have adequate or improved storage stability, in particular with regard to their enzymatic and preferably their amylolytic and/or proteolytic activity.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.